The present invention generally relates to an alarm system including multiple adverse condition detectors for detecting an adverse condition in a building. More specifically, the present invention is directed to a method and system for providing an improved method of determining which of the adverse condition detectors is sensing the adverse condition during the generation of an alarm signal by all of the adverse condition detectors.
Alarm systems which detect dangerous conditions in a home or business, such as the presence of smoke, carbon dioxide or other hazardous elements, are extensively used to prevent death or injury. In recent years, it has been the practice to interconnect different alarm units that are located in different rooms of a home. Specifically, smoke detecting systems for warning inhabitants of a fire include multiple detectors installed in the individual rooms of a home, and the detectors are interconnected so that the alarms of all the detectors will sound if only one detector senses any combustion products produced by a fire. In this way, individuals located away from the source of the combustion products are alerted as to the danger of fire, as well as those in closer proximity to the fire.
Although the generation of an audible alarm signal by each of the adverse condition detectors is an effective way to alert the building occupants that an adverse condition is occurring near one of the detectors, a desire exists to allow the occupants to rapidly determine which of the interconnected detectors is the detector actually sensing the adverse condition. This detector is often referenced to as the local detector.
One known method of indicating which of the adverse condition detectors is sensing the adverse condition is to activate a visual indicator on only the adverse condition detector that is sensing the adverse condition. Although this type of visual indication does allow the occupant to determine which of the detectors is generating the alarm condition, it requires the occupant to visually examine each of the alarms during the generation of the alarm signal. Thus, the occupant must allow the alarm signal to continue to operate while a visual inspection of each of the adverse condition detectors is undertaken.
Another system currently exists that disables the interconnect line extending between the multiple adverse condition detectors upon activation of a switch placed in the interconnected system. When the switch is activated, only the adverse condition detector sensing the adverse condition will continue to generate the alarm signal. The remaining remote alarm units are thus silenced for the entire duration of a predetermined silence period. In this manner, the occupants can simply depress a button or switch located somewhere within the building to disable the generation of the alarm signal by all of the adverse condition detectors except the adverse condition detector sensing the adverse condition and generating the local alarm signal. This system allows the occupant to more quickly determine which of the adverse condition detectors is sensing the adverse condition by listening for which of the detectors continues to generate the alarm signal after the switch has been activated.
In the prior art system identified above, the interconnect disabling circuit includes a timed feature such that the generation of the alarm signal by the remote interconnected adverse condition detectors is disabled for only a predetermined period of time, this period being preset at approximately ten minutes and subsequently enabled with each actuation of the appropriate button. However, during the entire duration of this disable period, the only alarm generating the alarm signal is the alarm sensing the adverse condition being sensed.
Although the alarm disable feature identified above is able to allow the occupant to more easily determine which of the adverse condition detectors is originating the alarm signal, disabling the generation of the alarm signal by the interconnected adverse condition detectors for an extended period of time may allow the occupants to fall into a momentary state of complacency. For instance, if the originating detector is in a distant corner or floor of a home, it may be either inaudible or diminished to a point that it does not call the occupant to immediate action. Since the point of having alarms sounding together is to provide the earliest warning of an adverse condition throughout the home, the disabling of the alarm signal by all of the interconnected adverse condition detectors for the entire disable period is not desirable.